This invention relates to a solid state MIC (microwave integrated circuit) oscillator using a transistor, an FET or some other solid state device, which has a superior temperature stability, and can be applied to a pump signal source for a microwave down-converter. It is known that a Gunn diode, an Impatt diode, a transistor or an FET may be used as a microwave solid-state oscillation device. A resonator such as a half-wavelength microstrip line, a YIG resonator, or a dielectric resonator is used for the oscillator to set an oscillation frequency condition.
Generally, the oscillation frequency of the solid state oscillator depends on ambient temperature more or less, and therefore, a resonator must have a high external Q value (therefore high unloaded Q) and good temperature characteristics. Though a dielectric resonator is very suitable for a MIC solid state oscillator because it satisfies the needed characteristics mentioned above, the size of the resonator increases below the frequency of a few GHz, and electromagnetic coupling to microstrip line becomes loose.
These problems might be solved if the dielectric resonator of high Q, high temperature stability and high dielectric constant, such as a few hundred, were realized. However, it has not been realized yet.
On the other hand, temperature compensation using the package which packs the device chip and which consists of a dielectric material having a negative dielectric temperature constant has been proposed, but it restricts the package or chip type and lacks capability of general application. A half wavelength microstrip line resonator cannot be used when the temperature stabilization is needed because of low unloaded Q such as under 300, though it is very simple and easy to design. Further a half wavelength strip line resonator consisting of a metal film which is deposited by thick-film process involving screening through a mask has a lower unloaded Q such as 100, and is still unsuitable for an oscillator.